1. Gymnosperms: “naked seeds”
Cycadophyta
Ginkophyta
Coniferaphyta
Gnetophyta

2. Seed plant recap: derived traits
Reduced—microscopic—gametophytes
Protected within sporophyte
Dependent on sporophyte for nutrients
Heterospory
different male and female reproductive structures
Ovules (develops into seed)
Pollen (containing sperm)
Protection of gametophyte from environment
Protects sperm and allows fertilization w/o water
Protects and enhances embryo survival

3. Gymnosperm Origins Fossil evidence for seedplants 360 m.y.a.
Among the Carboniferous forests of seedless vascular plants
Fossil evidence of extant Gymnosperms ~ 305 m.y.a.
Drying climate m.y.a. created environment where seedplants had an adaptive advantage proliferation of gymnosperms
Extant Angiosperms arose 200 m.y. after extant gymnosperms

4. Gymnosperm diversity 4 taxa Cycadophyta Ginkophyta Gnetophyta
Coniferaphyta – primary model

5. Cycadophyta (cycads) Very prolific in Carboniferous period
Flagellated sperm w/ in pollen tube
Palm like w/ stroboli (cones)
200+ species
Highly threatened today

6. Ginkophyta (Ginkos) Flagellated sperm w/ in pollen tube Deciduous
Looses leaves
Separate male and female plants (dioecious)
Females produce a fleshy seed that is stinky and undesirable…vomit like
1 species (not found in wild)
Long lived (up to 2500 yrs)

7. Gnetophyta Non-flagellated sperm Usually dioecious
Similarities w/ angiosperms
Has vessel members
Double fertilization
~70 species
Welwitschia

8. Distribution of Gnetophyta genera
gnetum
ephedra
welwitschia

9. Coniferaphyta (Conifers): pines, firs, cedars, junipers, spruces, etc.

10. Coniferous forest dominated regions of world

12. Conifers
~600 species
Mostly Northern Hemisphere—high latitudes & high altitudes/elevations
Non-flagellated sperm
Mostly Evergreen
Needle like or scale like leaves
Clusters of needles organized by fascicles
Cold Adapted
Many are mycorrhizal dependent
Commercially important
Lumber/timber-- Softwood (no fibers and thin tracheid walls)
Paper/wood pulp
Pine tar
Resin
turpentine

13. Southern Hemisphere Conifers

14. Pine Needle

15. Pine Needle

16. Cones = stroboli Most plants are monecious
Separate male and female cones

17. Male Cones & Pollen Formation

23. Pine Seeds: mostly winged some wingless varieties (birds, pine nuts
Pine Seeds: mostly winged some wingless varieties (birds, pine nuts..yum)